20
13 11 19 15 14 12 18 16 20 17 
13 11 20 18 16 19 15 14 12 17 
15 11 17 13 14 20 19 16 12 18 
17 11 16 13 12 19 14 20 15 18 
14 19 11 18 12 17 15 13 16 20 
19 13 18 20 15 16 12 14 17 11 
13 11 12 20 16 18 19 15 17 14 
20 13 19 16 18 12 11 17 14 15 
12 11 19 15 17 13 20 14 18 16 
18 13 16 17 12 14 15 19 20 11 
9 7 6 3 5 1 2 8 10 4 
4 8 2 7 10 9 6 5 1 3 
10 4 3 7 2 1 5 8 9 6 
2 6 5 1 4 3 10 9 7 8 
3 7 10 1 6 2 5 4 9 8 
6 3 4 1 8 9 5 10 7 2 
2 1 3 6 10 8 7 5 9 4 
5 9 10 6 4 2 1 7 8 3 
4 2 1 9 8 10 5 6 3 7 
5 9 8 4 3 6 7 2 10 1 
forbidden 1 12
forbidden 1 13
forbidden 1 16
forbidden 1 18
forbidden 2 11
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forbidden 2 17
forbidden 2 18
forbidden 2 20
forbidden 3 11
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forbidden 4 13
forbidden 4 15
forbidden 4 18
forbidden 5 17
forbidden 6 15
forbidden 6 16
forbidden 6 20
forbidden 7 11
forbidden 7 14
forbidden 7 15
forbidden 7 17
forbidden 8 11
forbidden 8 12
forbidden 8 13
forbidden 8 14
forbidden 8 20
forbidden 9 12
forbidden 9 14
forbidden 9 15
forbidden 9 16
forbidden 10 12
forbidden 10 13
forbidden 10 17
forbidden 10 18
forbidden 10 20